A High-Efficiency Charge-Pump Gate Drive Power Delivery Technique for Flying Capacitor Multi-Level Converters with Wide Operating Range

Abstract

In this work, we present a robust gate drive power delivery approach well-suited for converter topologies, such as the flying-capacitor multi-level (FCML) converter, that contain several series-connected switching elements. The proposed power delivery network leverages internal voltages inherent to the FCML topology in combination with a charge-pump mechanism to provide gate drive power with high efficiency. The charge-pump design operates independently of the primary switching devices, allowing the converter to operate at very low duty ratios without suffering from significant degradation of the floating supplies. The concept is validated in a hardware prototype, demonstrating an estimated 38% reduction in gate drive power delivery losses compared to competing techniques. Moreover, the robustness of the technique is validated through incorporation into a 400V, 2kW 6-level FCML DC-DC converter, achieving a 99.07% peak conversion efficiency and 2.05kW/in3 power density.